Rotary piston engine

ABSTRACT

A rotary piston engine in combination with a compressor and a burner for providing combustion by-product gases at high pressure to operate the rotary piston engine. The rotary piston engine is provided with a rotary valve for timing the introduction of the high pressure gas to the engine piston chambers.

United States Patent Michejda [54] ROTARY PISTON ENGINE v [7 21Inventor: Oskar Michejda, Fort Wayne, Ind.

[73] Assignee: Jadwiga Koltermann, London, En-

gland; a part interest [22] Filed: June 12, 1970 [21] Appl. No.: 45,840

52] u.s.c1. ..60/39.61,418/l96,418/199, 123/827 [511 1111.0. ..F02g 3/00[58] FieldofSearch ..60/39.6l,39.63,39.6; 123/345, 8.25; 418/196 [5 6]References Cited UNITED STATES PATENTS 1,933,442 10/1933 Maxwell..123/8.27

1451 Oct.3l, 1972 2,476,397 7/1949 Bary ..60/39.6l X 2,631,428 3/1953Shames ..60/39.61 X 1,766,519 6/1930 Johnson ..418/196 2,786,332 3/1957Taverniers ..60/39.61 1,983,216 12/1934 Carter ..418/196 3,274,943 9/ l966 Berry ..418/196 3,116,666 1/1964 Scott ..418/196 X PrimaryExaminer-Clarence R. Gordon Attorney-Harness, Dickey & Pierce [57ABSTRACT A rotary piston engine in combination with a compressor and aburner for providing combustion by-product gases at high pressure tooperate the rotary piston engine. The rotary piston engine is providedwith a rotary valve for timing the introduction of the high pressure gasto the engine piston chambers.

11 Claims, 8 Drawing Figures PATENTEDucrsw 1972 3.701. 254

sum 3 or a INVENTO 06%47 7 BY g ml a AJL ROTARY PISTON ENGINE BACKGROUNDOF THE INVENTION 1. Field of the Invention This invention relates toengines, and more particularly, rotary piston engines.

2. Description of the Prior Art Various engines are known to the artwhich use three rotating pistons and a central rotor engaging the-bodyof each piston. More speciflcaly, the pistons are mounted for rotationwithin a piston chamber and are provided with a projection for sealinglyengaging the wall of the chamber. The central rotor is provided with arecess and is geared to the pistons such that the projection on thepistons will be accepted by the recess as the projections rotate intoalignment therewith. The piston projection and the engagement of therotor with the piston body define an expanding chamber portion and acontracting chamber portion within each piston chamber. These enginesare generally characterized by several operating deficiencies, forexample, the lack of an adequate provision for preventing decompressionwithin the expanding chamber and compression within the contractingchamber thereby wastefully consuming significant amounts of energy.Moreover, the working portion of the rotational cycle of the piston isoften quite short so as to require a relatively large engine for a givenpower output.

Engines using compressors and burners for providing combustionby-product gas in combination with means for extracting mechanicalenergy from the combustion by-product gases also known. For example, gasturbine engines fall within this category. However, these enginesconvert the kinetic energy of the combustion byproduct gases intomechanical energy which results in low torque levels at low gas flowvelocities, i.e., at low turbine rotational velocities. Furthermore, gasturbine engines require intricate parts with close tolerancesresultingin notoriously high manufacturing costs. In short due to various designand operational cycle deficiencies, the prior art engine designs fallshort of.

SUMMARY OFTHE INVENTION The present invention provides a rotary pistonengine which receives combustion by-product gases and converts thepressure energy of the combustion byproduct gases into useful mechanicalenergy. Preferably, the rotary piston engine is used in combination withan air compressor and fuel burner for providing the combustionby-product gases. The engine is advantageously characterized byobtaining a relatively large torque on the output shaft for a largerange of engine rotational velocities including relatively lowrotational velocities, and moreover, achieves substantially completecombustion of the gas mixture to obtain low emission rates of exhaustelements causing air pollution.

An exemplary rotary piston engine according to the present invention isdescribed which has, as an additional feature, a novel rotary valve andcooperating port system. The rotary valve and port arrangement of thepresent invention is arranged to prevent compression of the contractingvolume in the rotary piston chamber, decompression of the expandingvolume, and moreover, achieves these functional advantages using anuncomplicated rotating valve member.

The engine of the present invention uses parts which rotate rather thanreciprocate, and therefore, are easy to balance dynamically. Also, areduction of fuel consumption is achieved as comparedwith thefuel'consumption of conventional reciprocating piston engines sinceincreased times of combustion may be readily incorporated to provide amore complete combustion of a gas mixture, which also results in lowrates of pollutant emission. As an additional advantage, fuels withoutlead or other octane-increasing ingredients may be used since there isno high compression fuel-ignition system utilized. There advantages areachieved with a relatively simple power mechanism with a minimum numberof parts, and accordingly, an inexpensive mechanism as compared to themore complicated reciprocating piston engines and the extremely costlygas turbines.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall functionaldiagram of an exemplary engine system according to this invention;

FIG. 2 is a side cross-sectional view of an exemplary rotary pistonengine, suitable for use with the engine system of FIG. 1, having anovel valve and port arrangement;

FIG. 3 is an end cross-sectional view of the rotary piston engine ofFIG. 2 taken generally along the lines 33 so as to illustrate the rotarypistons in their operating positions;

FIG. 4 is another end cross-sectional view of the rotary piston engineof FIG. 2 taken generally along the lines 44 so as to illustrate thegear train of the engine;

FIG. 5 is yet another end cross-sectional view of the rotary pistonengine of FIG. 2 taken generally along the lines 55 so as to illustratethe rotary valve of the engine;

FIG. 6 is still another'end cross-sectional view of the rotary pistonengine of FIG. 2 taken generally along the lines 66 so as to illustratethe ports downstream of the rotary valve of FIG. 5;

FIG. 7 is an end view of the rotary piston engine of FIG. 2 looking inthe direction of arrows 7 7 so as to illustrate the inlet port of theengine; and

FIG. 8 is another end view of the rotary piston engine of FIG. 2 lookingin the direction of the arrows 88 so as to illustrate the exhaust portand plenum of the engine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, a diagram isshown illustrating an exemplary engine system 10 according to thepresent invention. The system 10 includes a rotary piston engine 12having an output shaft for delivering mechanical energy, for example, tothe driven wheels of a motor vehicle, and an accessory shaft for drivingan air compressor indicated generally at 14. A burner, also indicatedgenerally at 14, receives compressed air from the compressor and fuelfrom a fuel pump 16 to provide combustion by-product gases at elevatedpressure which are delivered to the rotary piston engine 12.

In FIG. 2, an exemplary rotary piston engine 12 is illustrated which issuitable for use with the engine system of FIG. 1. The rotary pistonengine 12 has a housing 18 including an inlet opening 20 for receivingcombustion by-product gases from the burner and an exhaust or outletopening 22 for exhausting expended gases from the engine 12. The rotarypiston engine 12 further has a main output shaft 24 for rotating thedriven wheels of a vehicle or other power-accepting device and anauxiliary shaft 26 for operating, for example, the compressor and thefuel pump of the system 10 with which it is incorporated.

The rotary piston engine 12 and the housing 18 are generally of stackedconstruction to provide a structure which is inexpensive to build andmaintain. More specifically, the housing 18 may include, from left toright, an inlet end plate 28, a valve surround plate 30, a valve portplate 32, a left bearing support plate 34, a left rotary piston sealplate 36, a rotary piston chamber section 38, a right rotary piston sealplate 40, a right bearing support plate 42, a gear train housing 44, anoutlet end plate 46, and an exhaust plenum cover 48.

With reference now to FIG. 3, it will be seen that the rotary pistonengine 12 has three identical rotary pistons 50, 52, and 54 mounted forrotation by bearings at each end (as best seen in FIG. 2) such that theaxes of rotation are positioned at the apexes of an imaginaryequilateral triangle. The rotary pistons 50-54 each consists of acylindrical body portion and a projecting portion 56, 58, or 60,respectively, which sealingly engage the wall of the cylindricalchambers 62, 64, and 66, respectively. The projections 56-60 may beprovided with a radially outward biased seal member to effect the sealbetween the projection and the chamber wall such as is now the practicewith Wankel engine rotors. A central drum 68, having a diameter equal tothe body diameters of the pistons 50-54, is provided which is alsoadapted for rotation by bearings at each end as illustrated in FIG. 2.The locations of the rotary pistons 50-54 and the central drum 68 areestablished to provide sealing engagement between the central drum andthe body portions of the rotary pistons 50-54. The central drum 68 isprovided with a recess 70 having a configuration generally adapted toindividually accept each projection 5660 in cyclic order.

With reference now to FIG. 4, a gear train for the rotary piston engine12 is illustrated having a central gear 72 affixed to the central drum68 for rotation therewith and identical outlying gears 74, 76, and 78secured to the rotary pistons 50-54, respectively, and engaged with thecentral gear 72 for rotation therewith. The gears 72-78 are engaged torotationally time the pistons 50-54 at 120 intervals with respect to theengagement of the respective projections with rotating drum 68.Specifically, if the dead center engagement of the projection 56 withthe recess 70 is considered to be a reference point, 120 of additionalrotation will occur prior to dead center engagement of the projection 60with the recess 70, and 240 of additional rotation will occur prior todead center engagement of the projection 58 with the recess 70.

Referring again to FIG. 2, it can be seen that the central drum 68 has,as an integral part thereof, the main output shaft 24 and the accessorydrive shaft 26. Each of the rotary pistons 50-54 is adapted forclockwise rotation whereas the central drum 68 is adapted forcounterclockwise rotation. As a consequence of this rotational schemeand the equal diameters of the body portions of the rotary pistons 50-54and the central drum 68, a non-sliding seal is effected between thecentral drum 68 and each rotary piston. Consequently, wear of thepistons 50-54 and drum 68 is minimized.

It can be seen in FIG. 3 that each of the rotary pistons 5054 form anannular chamber or volume which is divided into two portions, each beingdefined by the engagement of the projection with the wall and thecontact between the central drum and the rotary piston.

With reference to both FIGS. 2 and 3, a plurality of inlet ports areprovided which communicate the rotary piston chamber 66 with an inletduct 82, which in turn communicates with an inlet plenum 84 at selectedtimes as determined by the rotational position of a rotary valve disc86. The inlet plenum 84 communicates at all times with the inlet opening20. In a similar manner, a plurality of inlet ports 88 are provided forthe piston chamber 62 and a plurality of inlet ports 90 are provided forthe pistonchamber 64. The inlet ports 88 and 90 are communicated withinlet ducts 92 and 94, respectively, which also communicate with theinlet plenum 84 at selected times in accordance with the rotationalposition of the rotary valve disc 86. With reference to FIG. 6, it canbe seen that the inlet ducts 82, 92, and 94 have openings which areradially equidistant from the axis of the central drum 68 and are spacedat rotational intervals of 120". Also, with reference to FIGS. 2 and 3,a plurality of exhaust ports 96 are provided for the rotary pistonchamber 64 communicating with an exhaust duct 98 which at all timescommunicates with the exhaust opening 22. In similar manner, exhaustports I00 and 102 are provided for chambers 62 and 66, respectively,which communicate with exhaust ducts 104 and 106, respectively. Theexhaust ducts I04 and 106 communicate at all times with the exhaustopening 22 through an exhaust plenum within the cover 48 as can be bestseen in FIG. 8. As can be seen in the drawings, the inlet ports 80, 88and 90 and the exhaust ports 96, and 102 are located on opposite sidesof the contact between the central drum 68 and the respective pistonsand are located in close proximity thereto for purposes to be explainedhereinafter. Preferably, the rotational interval from the inlet ports tothe exhaust ports should be as large as possible, for example, at least180, and preferably, approximately 270.

The rotary valve 86 is secured to a shaft 108 which is integral with theauxiliary output shaft 26 and the central drum 68 for rotationtherewith. As can be best seen in FIG. 5, the valve disc 86 has anarcuate opening 110 extending so as to subtend an arc of nearly which isradially aligned with the openings of inlet ducts 82, 92 and 94. Araised portion or boss 112 surrounds the arcuate opening 1101')" eachside of the disc 86. A closed recess portion 113 is provided radiallyopposite the opening 1 10 so as to facilitate dynamic balancing of thevalve disc 86. The boss 112 of the valve disc 86 closely cooperates withthe seal plates 28 and 32 on each side thereof so as to effect asubstantial fluid seal therebetween. In the position shown in FIG. 5,the valve disc 86 is communicating the inlet plenum 84 with the inletduct 94 (shown also in FIG. 6) of the rotary piston chamber 64.Accordingly, high pressure gases from the burner will be communicated tothe rotary piston chamber 64. Also, in the position shown in FIG. 5, theopening 110 is about to become aligned with the inlet duct 92 for therotary piston chamber 62. For at least a portion of the operating cycle,both rotary piston chambers 62 and 64 will be receiving high pressuregases from the inlet plenum 84.

As can be seen in the drawings, the rotary piston engine 12 ispreferably provided with a plurality of cooling passages 114 whichextend through the engine and are adapted to receive a coolant solutionfor flow therethrough.

In operation, combustion by-product gases at elevated pressures areintroduced to the inlet opening 20, and thereafter, are directed inaccordance with the position of the rotary valve 86 to one or two of theinlet ports 80, 88, or 90. Referring now to piston chamber 62 of FIG. 3,it can be seen that an annular chamber portion 116, defined by theprojection 56 and the engagement of the piston body with the rotary drum68, receives the combustion by-product gases from the inlet ports 88.The pressure of the gas in the chamber 116 will act upon the rotarypiston 50 to cause it to rotate clockwise such that the volume 116 willexpand. It can also be seen that an annular chamber portion 118, alsodefined by the projection 56 and the engagement of the piston body withthe rotary drum 68, will contract during the rotation of the rotarypiston 50. As the rotary piston 50 rotates, useful torque and power istransmitted to the output shafts 24 and 26 through its associated spurgear 74 and the spur gear 72 of the central drum 68 in substantialaccordance with the pressure energy of the gases delivered to thechamber 62. The outlet ports 100, which as previously stated are alwaysopen to the exhaust port 22, prevent a pressure rise in the contractingannular chamber portion 118 so as to avoid wasteful expenditure ofenergy. After a rotation of approximately 180, the passage from theinlet opening 22 to the inlet ports 88 is closed by the valve disc 86.At this time, the elevated pressure gases will force the projection 56on the rotary piston 50 to move further until, after additional work, itpasses the exhaust ports 100 to vent the pressure within the expandingannular chamber portion 116 to atmosphere through the exhaust opening22. The valve disc maintains the inlet ports 88 closed with respect tothe inlet opening as the projection 56 continues in its clockwisemovement past the recess 70 until it reaches the trailing edge of theinlet ports 88 at which time the annular slot 110 of the valve disc 86is again Positioned to provide flow of high pressure gases into theexpanding annular chamber portion 116. Similar cycles will take placewith respect to the other rotary pistons 52 and 54, only. with anoperating lag of 120 and 240", respectively, so as to provide a poweroutput in substantial accordance with the pressure energy of combustionby-prQductgases delivered to piston chambers 64 and 66, respectively. Itwill be appreciated that the power outputs of the rotary pistons 50-54are combined by an engagement of the gears 72-76 with the central gear78 so as to deliver a combined power output on shafts 24 and 26.

In view of the above description, it now will be appreciated that thepresent invention provides an engine having high torque and power outputover a wide range of rotational velocities. Moreover, it has lower ratesof pollutant emission that conventional reciprocating piston engines.The engine of this invention can be constructed at a cost competitivewith conventional reciprocating engines. Furthermore, it provides theadvantages of a turbine engine in that it uses rotating rather thanreciprocating parts, and yet, it does not have the disadvantage ofturbine engines of low torque output at low rotational velocities.

While it will be apparent that the teachings herein are well calculatedto teach one skilled in the art the method of making the preferredembodiment of this invention, it will be appreciated that the inventionis susceptible to modification, variation and change without departingfrom the proper scope or meaning of the subjoined claims.

What is claimed is:

1. An engine system comprising:

a source of fuel;

burner means receiving fuel from said source for combusting said fuel toprovide combustion byproduct gas at elevated pressure; and

rotary engine means, including:

housing means having inlet opening means, outlet opening means, and aplurality of generally cylindrical rotary piston chambers with eachchamber having a wall; a rotary piston mounted for rotation about anaxis within each of said chambers having a cylindrical body and aprojection therefrom effecting a substantial gaseous seal with therespective chamber wall, said body forming a substantially annularchamber with said respective chamber wall, said annular chamber beinginterrupted by said projection, the axis of each of said rotary pistonsbeing in parallel relation each with the other and equidistantlyradially disposed from a predetermined central axis;

a rotary seal means engaging each of said cylindrical piston bodies andincluding a recess for accepting each of said projections, said rotaryseal means being adapted for rotation about said central axis inaccordance with the rotation of said rotary pistons to providesequential acceptance of each of said projections on each rotation ofsaid rotary seal means, said rotary seal means and each of saidprojections defining an expanding annular chamber portion and acontracting annular chamber portion in each of said rotary pistonchambers;

inlet port means located in each of said rotary piston chamber walls,each communicating with a respective one of said expanding annularchamber portrons;

outlet port means located in each of said chamber walls, eachcommunicating with a respective one of said contracting annular chamberportions with said housing outlet opening means at least at certaintimes, each said outlet port means being separated from the respectiveone of said inlet port means by a predetermined rotational interval; anda rotary valve plate mounted for rotation about said central axis withsaid rotary seal means having a single opening communicating saidhousing inlet opening means with each of said inlet port means for atleast a portion of each rotational period between adjacent location ofrespective ones of said projection with the respective ones of saidinlet port means and adjacent location of said respective one projectionwith the respective one of said outlet port means'said housing inletopening means receiving said combustion by-product gas for rotating saidpistons to provide a mechanical power output in substantial accordancewith the pressure energy of said gas.

2. An engine system according to claim 1 further including compressormeans for providing oxygen containing gas at elevated pressure to saidburner means for combustion of said fuel.

3. An engine system according to claim 2 including power transmissionmeans for transmitting power from rotary engine means to said compressormeans for operation thereof.

4. An engine system according to claim 3 wherein said power transmissionmeans is a mechanical connection between said rotary piston and saidcompressor means.

5. An engine system according to claim 1 wherein said rotary valve platehas a generally arcuate opening and an arcuate length providingcommunication of said combustion by-product gas with said expandingannular chamber portion for a substantial portion of said period.

6. An engine system according to claim 1 wherein said rotary seal meanshas affixed thereto an output shaft for providing a combined poweroutput of said plurality of rotary pistons.

7. An engine system according to claim 1 having three rotary pistons.

8. A rotary engine comprising:

housing means having inlet opening means, outlet opening means, and aplurality of generally cylindrical rotary piston chambers with eachchamber having a wall;

a rotary piston mounted for rotation about an axis within each of saidchambers having a cylindrical body and a projection therefrom effectinga substantial gaseous seal with the respective chamber wall, said bodyforming a substantially annular chamber with said respective chamberwall, said annular chamber being interrupted by said projection, theaxis of each of said rotary pistons being in parallel relation each withthe other and equidistantly radially disposed from a predeterminedcentral axis;

a rotary seal means engaging each of said cylindrical piston bodies andincluding a recess for accepting each of said projections, said rotaryseal means being adapted for rotation-about said central axis inaccordance with the rotation of said rotary pistons to providesequential acceptance of each of said projections on each rotation ofsaid rotary seal means, said rotary seal means and each of saidprojections defining an expanding annular chamber portion and acontracting annular chamber portion in each of said rotary pistonchambers; inlet port means located in each of said rotary piston chamberwalls, each communicating with a respective one of said expandingannular chamber portions;

outlet port means located in each of said chamber walls, eachcommunicatingwith a respective one of said contracting annular chamberportions with said housing outlet opening means at least at certaintimes, each said outlet port means being separated from the respectiveone of said inlet port means by a predetermined rotational interval; and

a rotary valve plate mounted for rotation about said central axis withsaid rotary seal means having a single opening communicating saidhousing inlet opening means with each of said inlet port means for atleast a portion of each rotational period between adjacent location ofrespective ones of said projection with the respective ones of saidinlet port means and adjacent location of said respective one projectionwith the respective one of said outlet port means such that pressurecommunicated to said inlet opening will cause pressure responsiverotation of said rotary piston.

9. An engine system according to claim 8 wherein said rotary valve platehas a generally arcuate opening and an arcuate length providingcommunication of said housing inlet opening means with said expandingannular chamber portion for a substantial portion of said period.

10. An engine system according to claim 8 wherein said rotary seal meanshas affixed thereto an output shaft for providing a combined poweroutput of said plurality of said rotary pistons.

11. An engine system according to claim 8 having three rotary pistons.

1. An engine system comprising: a source of fuel; burner means receivingfuel from said source for combusting said fuel to provide combustionby-product gas at elevated pressure; and rotary engine means, including:housing means having inlet opening means, outlet opening means, and aplurality of generally cylindrical rotary piston chambers with eachchamber having a wall; a rotary piston mounted for rotation about anaxis within each of said chambers having a cylindrical body and aprojection therefrom effecting a substantial gaseous seal with therespective chamber wall, said body forming a substantially annularchamber with said respective chamber wall, said annular chamber beinginterrupted by said projection, the axis of each of said rotary pistonsbeing in parallel relation each with the other and equidistantlyradially disposed from a predetermined central axis; a rotary seal meansengaging each of said cylindrical piston bodies and including a recessfor accepting each of said projections, said rotary seal means beingadapted for rotation about said central axis in accordance with therotation of said rotary pistons to provide sequential acceptance of eachof said projections on eAch rotation of said rotary seal means, saidrotary seal means and each of said projections defining an expandingannular chamber portion and a contracting annular chamber portion ineach of said rotary piston chambers; inlet port means located in each ofsaid rotary piston chamber walls, each communicating with a respectiveone of said expanding annular chamber portions; outlet port meanslocated in each of said chamber walls, each communicating with arespective one of said contracting annular chamber portions with saidhousing outlet opening means at least at certain times, each said outletport means being separated from the respective one of said inlet portmeans by a predetermined rotational interval; and a rotary valve platemounted for rotation about said central axis with said rotary seal meanshaving a single opening communicating said housing inlet opening meanswith each of said inlet port means for at least a portion of eachrotational period between adjacent location of respective ones of saidprojection with the respective ones of said inlet port means andadjacent location of said respective one projection with the respectiveone of said outlet port means said housing inlet opening means receivingsaid combustion by-product gas for rotating said pistons to provide amechanical power output in substantial accordance with the pressureenergy of said gas.
 2. An engine system according to claim 1 furtherincluding compressor means for providing oxygen containing gas atelevated pressure to said burner means for combustion of said fuel. 3.An engine system according to claim 2 including power transmission meansfor transmitting power from rotary engine means to said compressor meansfor operation thereof.
 4. An engine system according to claim 3 whereinsaid power transmission means is a mechanical connection between saidrotary piston and said compressor means.
 5. An engine system accordingto claim 1 wherein said rotary valve plate has a generally arcuateopening and an arcuate length providing communication of said combustionby-product gas with said expanding annular chamber portion for asubstantial portion of said period.
 6. An engine system according toclaim 1 wherein said rotary seal means has affixed thereto an outputshaft for providing a combined power output of said plurality of rotarypistons.
 7. An engine system according to claim 1 having three rotarypistons.
 8. A rotary engine comprising: housing means having inletopening means, outlet opening means, and a plurality of generallycylindrical rotary piston chambers with each chamber having a wall; arotary piston mounted for rotation about an axis within each of saidchambers having a cylindrical body and a projection therefrom effectinga substantial gaseous seal with the respective chamber wall, said bodyforming a substantially annular chamber with said respective chamberwall, said annular chamber being interrupted by said projection, theaxis of each of said rotary pistons being in parallel relation each withthe other and equidistantly radially disposed from a predeterminedcentral axis; a rotary seal means engaging each of said cylindricalpiston bodies and including a recess for accepting each of saidprojections, said rotary seal means being adapted for rotation aboutsaid central axis in accordance with the rotation of said rotary pistonsto provide sequential acceptance of each of said projections on eachrotation of said rotary seal means, said rotary seal means and each ofsaid projections defining an expanding annular chamber portion and acontracting annular chamber portion in each of said rotary pistonchambers; inlet port means located in each of said rotary piston chamberwalls, each communicating with a respective one of said expandingannular chamber portions; outlet port means located in each of saidchamber walls, each communicating with a respective one of saidcontracting annular chamber portiOns with said housing outlet openingmeans at least at certain times, each said outlet port means beingseparated from the respective one of said inlet port means by apredetermined rotational interval; and a rotary valve plate mounted forrotation about said central axis with said rotary seal means having asingle opening communicating said housing inlet opening means with eachof said inlet port means for at least a portion of each rotationalperiod between adjacent location of respective ones of said projectionwith the respective ones of said inlet port means and adjacent locationof said respective one projection with the respective one of said outletport means such that pressure communicated to said inlet opening willcause pressure responsive rotation of said rotary piston.
 9. An enginesystem according to claim 8 wherein said rotary valve plate has agenerally arcuate opening and an arcuate length providing communicationof said housing inlet opening means with said expanding annular chamberportion for a substantial portion of said period.
 10. An engine systemaccording to claim 8 wherein said rotary seal means has affixed theretoan output shaft for providing a combined power output of said pluralityof said rotary pistons.
 11. An engine system according to claim 8 havingthree rotary pistons.